1. Field of the Invention
The present invention relates to a method of computing the overall mechanical material constant, as a mechanical characteristic, of a composite material which includes material components having known material constants embedded in a matrix phase having a known material constant. Additionally, the present invention relates to a method of computing the volume fraction of a material component in a composite material in which other material components having known material constants are dispersed in a matrix phase having a known material constant. Furthermore, the present invention relates to a recording medium storing a program for causing a computer to execute the aforementioned methods.
2. Description of the Related Arts
Conventionally, a variety of attempts have been actively employed for accurately estimating the mechanical characteristic of a composite material in which predetermined material components are dispersed in a matrix phase. The estimation intends to efficiently identify a variety of factors using a computer for tailoring the composite material to have a desired characteristic, instead of finding them by an actual experiment. For example, the factors may include identification of the mechanical characteristics of the material components in the composite material and the volume fractions of the material components. As a result, it is possible to design a mixture of components with desired characteristics in an early stage.
Under the circumstance, JP-A-2007-122242 discloses a method for analyzing a macro-structure which consists of multiple minute elements in which a micro-structure that has a three-dimensionally heterogeneous deformation characteristic is repeated periodically in one direction. In the publication, the homogenized elastic modulus is computed by identifying a unit cell (i.e., a periodic unit in the macro-structure) and assuming the unit cell to have a homogeneous material characteristic. Subsequently, the macro-structure is modeled by assuming that it has a homogenized elastic characteristic. Then, a macro-scale analysis is executed for computing the deformation of the macro-structure at a given position in the direction of the periodical arrangement. Furthermore, a local analysis is executed. In the local analysis, the obtained deformation of the macro-structure at a given position in the direction of the periodical arrangement is applied to the minute elements forming the unit cell arranged in the position, and local responses are obtained from the minute elements.
According to the publication, the structural analysis method is capable of reducing a period of time required for the structural computation of the macro-structure which is heterogeneous on its cross-section.
However, the structural analysis method is executed using a finite element model formed with minute elements. Accordingly, the method has a drawback in that a long period of time is necessary for generation of a model and computation and it cannot be thereby a useful means for time-critical initial design and development in the early stage.
On the other hand, a classical analytical model, using a spring and a dash pot, has also been conventionally used for computing the mechanical characteristic of composite materials. The model spends a short period of time for computation, and is efficient in this regard. However, the micro-state of a composite material cannot be taken into account in the model. Therefore, the model also has a drawback in that a computational result does not include much information and thereby the computational result is not accurate.